I would appreciate any feedback from you regarding finishing the interior pine side of an out-swing french door patio door. After applying a conditioner (per Minwax's recommendation) I am considering applying a gel stain. Is any sanding necessary?
Yes, sanding is needed to remove any mill glaze from the boards used. This should be about 100 grit paper, sanded with the grain or with an orbital sander. I prefer gell stain, myself. I apply it with a rag and rub it in good. I would not sand after the stain. Put the first coat of finish on then sand very lightly with 220 grit between layers to remove any dust and grain raise. I like using the Varathane product called Professional finish. It comes in a black label, it is oil based, but dries fast. I don't like to use a finish and stain in one application. If you want the stain darker or lighter it is sealed and can't be re-stained without removing the clear finish. Minwax is a good product, I've just had experience with the Varathane products.